Handle touchpad flings with passive event listeners on compositor thread.

content/renderer/input/input_event_filter.h

Index: content/renderer/input/input_event_filter.h
diff --git a/content/renderer/input/input_event_filter.h b/content/renderer/input/input_event_filter.h
index 6ebe7f42515ef04d75f99605450120e56620fc16..a1f4a04f0f14fd389a99d55444cb7a922aafa091 100644
--- a/content/renderer/input/input_event_filter.h
+++ b/content/renderer/input/input_event_filter.h
@@ -68,6 +68,11 @@ class CONTENT_EXPORT InputEventFilter : public InputHandlerManagerClient,
                      const ui::DidOverscrollParams& params) override;
   void DidStartFlinging(int routing_id) override;
   void DidStopFlinging(int routing_id) override;
+  void DispatchNonBlockingEventToMainThread(
+      int routing_id,
+      ui::ScopedWebInputEvent event,
+      const ui::LatencyInfo& latency_info) override;
+
   void NotifyInputEventHandled(int routing_id,
                                blink::WebInputEvent::Type type,
                                InputEventAckState ack_result) override;